Question

What is meant by zero error of a vernier
callipers ? How is it determined ? Draw neat
diagrams to explain it. How is it taken in account
to get the correct measurement ?​

Answer 1

Sometimes, due to a mechanical error in vernier callipers, the zero mark of the vernier scale does not coincide with zero mark of main scale when the two jaws are in contact. It is then said to have zero error.

Zero error is always algebraically subtracted from the measured length. If the zero of the vernier scale lies to the right of the main scale the zero error is positive and if it lies to the left of the main scale then it is negative.